Index: firmware/App/Services/MsgQueues.h
===================================================================
diff -u -r6c60d0d0300828750c76f2e397d4e7ccaa84bbb2 -r169b72cc9c959b53b40b48e9ce0a5f4aeca1de97
--- firmware/App/Services/MsgQueues.h	(.../MsgQueues.h)	(revision 6c60d0d0300828750c76f2e397d4e7ccaa84bbb2)
+++ firmware/App/Services/MsgQueues.h	(.../MsgQueues.h)	(revision 169b72cc9c959b53b40b48e9ce0a5f4aeca1de97)
@@ -32,9 +32,7 @@
 #pragma pack(push,1)
 typedef struct
 {
-#ifndef ACK_NOT_IMPLEMENTED
     S16 seqNo;                                  // sequence # (and ACK required bit) of message
-#endif
     U16 msgID;                                  // ID of message
     U08 payloadLen;                             // length of payload in bytes
 } MESSAGE_HEADER_T;
Index: firmware/App/Services/SystemComm.c
===================================================================
diff -u -r2e6c750c202b7361d79488ce383e34f380e75413 -r169b72cc9c959b53b40b48e9ce0a5f4aeca1de97
--- firmware/App/Services/SystemComm.c	(.../SystemComm.c)	(revision 2e6c750c202b7361d79488ce383e34f380e75413)
+++ firmware/App/Services/SystemComm.c	(.../SystemComm.c)	(revision 169b72cc9c959b53b40b48e9ce0a5f4aeca1de97)
@@ -114,9 +114,7 @@
     //static U32 dbgRcvFromDialinIdx = 0;
 #endif
 
-#ifndef ACK_NOT_IMPLEMENTED
 static PENDING_ACK_RECORD_T pendingAckList[ PENDING_ACK_LIST_SIZE ];    // list of outgoing messages that are awaiting an ACK
-#endif
 
 static volatile BOOL dgIsCommunicating = FALSE;         // has DG sent a message since last check
 static U32 timeOfLastDGCheckIn = 0;                     // last time DG checked in
@@ -162,10 +160,8 @@
 static void checkForCommTimeouts( void );
 static void checkTooManyBadMsgCRCs( void );
 
-#ifndef ACK_NOT_IMPLEMENTED
 static BOOL matchACKtoPendingACKList( S16 seqNo );
 static void checkPendingACKList( void );
-#endif
 
 /*************************************************************************
  * @brief initSystemComm
@@ -191,13 +187,11 @@
         badCRCTimeStamps[ i ] = 0;
     }
 
-#ifndef ACK_NOT_IMPLEMENTED
     // initialize pending ACK list
     for ( i = 0; i < PENDING_ACK_LIST_SIZE; i++ )
     {
         pendingAckList[ i ].used = FALSE;
     }
-#endif
 }
 
 /*************************************************************************
@@ -305,10 +299,8 @@
     // check for sub-system comm timeouts
     checkForCommTimeouts();
 
-#ifndef ACK_NOT_IMPLEMENTED
     // check ACK list for messages that need to be re-sent because they haven't been ACK'd
     checkPendingACKList();
-#endif
 }
 
 /*************************************************************************
@@ -945,23 +937,19 @@
         {   // CRC should be good because we checked it during parsing before adding to queue - but check it again for good measure
             if ( message.crc == crc8( (U08*)(&message), sizeof(MESSAGE_HEADER_T) + message.msg.hdr.payloadLen ) )
             {
-#ifndef ACK_NOT_IMPLEMENTED
                 // if ACK, mark pending message ACK'd
                 if ( MSG_ID_ACK == message.msg.hdr.msgID )
                 {
                     matchACKtoPendingACKList( message.msg.hdr.seqNo );
                 }
                 else
-#endif
                 {
-#ifndef ACK_NOT_IMPLEMENTED
                     // if received message requires ACK, queue one up
                     if ( message.msg.hdr.seqNo < 0 )
                     {
                         sendACKMsg( &message.msg );
                     }
                     else
-#endif
                     {   // otherwise, process the received message
                         processReceivedMessage( &message.msg );
                     }
@@ -1033,7 +1021,6 @@
     }
 }
 
-#ifndef ACK_NOT_IMPLEMENTED
 /*************************************************************************
  * @brief addMsgToPendingACKList
  * The addMsgToPendingACKList function adds a given message to the pending \n
@@ -1146,7 +1133,6 @@
         }
     }
 }
-#endif
 
 /*************************************************************************
  * @brief processReceivedMessage
Index: firmware/App/Services/SystemComm.h
===================================================================
diff -u -r2e6c750c202b7361d79488ce383e34f380e75413 -r169b72cc9c959b53b40b48e9ce0a5f4aeca1de97
--- firmware/App/Services/SystemComm.h	(.../SystemComm.h)	(revision 2e6c750c202b7361d79488ce383e34f380e75413)
+++ firmware/App/Services/SystemComm.h	(.../SystemComm.h)	(revision 169b72cc9c959b53b40b48e9ce0a5f4aeca1de97)
@@ -53,8 +53,6 @@
 BOOL isDGCommunicating( void );
 BOOL isUICommunicating( void );
 BOOL uiCommunicated( void );
-#ifndef ACK_NOT_IMPLEMENTED
 BOOL addMsgToPendingACKList( MESSAGE_T *msg, COMM_BUFFER_T channel, U08 *msgData, U32 len );
-#endif
 
 #endif
Index: firmware/App/Services/SystemCommMessages.c
===================================================================
diff -u -r2e6c750c202b7361d79488ce383e34f380e75413 -r169b72cc9c959b53b40b48e9ce0a5f4aeca1de97
--- firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision 2e6c750c202b7361d79488ce383e34f380e75413)
+++ firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision 169b72cc9c959b53b40b48e9ce0a5f4aeca1de97)
@@ -128,7 +128,6 @@
     data[ msgSize++ ] = MESSAGE_SYNC_BYTE;
 
     // set sequence # and ACK bit (unless this is an ACK to a received message)
-#ifndef ACK_NOT_IMPLEMENTED
     if ( msg.hdr.msgID != MSG_ID_ACK )
     {
         // thread protect next sequence # access & increment
@@ -141,7 +140,6 @@
             msg.hdr.seqNo *= -1;
         }
     }
-#endif
 
     // calculate message CRC
     crc = crc8( (U08*)(&msg), sizeof( MESSAGE_HEADER_T ) + msg.hdr.payloadLen );
@@ -165,7 +163,6 @@
         data[ msgSize++ ] = 0;
     }
 
-#ifndef ACK_NOT_IMPLEMENTED
     // if ACK required, add to pending ACK list
     if ( TRUE == ackReq )
     {
@@ -175,7 +172,6 @@
             SET_ALARM_WITH_1_U32_DATA( ALARM_ID_SOFTWARE_FAULT, SW_FAULT_ID_MSG_PENDING_ACK_LIST_FULL )
         }
     }
-#endif
 
     if ( FALSE == error )
     {
@@ -186,7 +182,6 @@
     return result;
 }
 
-#ifndef ACK_NOT_IMPLEMENTED
 /*************************************************************************
  * @brief sendACKMsg
  * The sendACKMsg function constructs and queues for transmit an ACK message \n
@@ -216,7 +211,6 @@
 
     return result;
 }
-#endif
 
 // ***********************************************************************
 // ********************* MSG_ID_OFF_BUTTON_PRESS *************************
Index: firmware/App/Services/SystemCommMessages.h
===================================================================
diff -u -r2e6c750c202b7361d79488ce383e34f380e75413 -r169b72cc9c959b53b40b48e9ce0a5f4aeca1de97
--- firmware/App/Services/SystemCommMessages.h	(.../SystemCommMessages.h)	(revision 2e6c750c202b7361d79488ce383e34f380e75413)
+++ firmware/App/Services/SystemCommMessages.h	(.../SystemCommMessages.h)	(revision 169b72cc9c959b53b40b48e9ce0a5f4aeca1de97)
@@ -91,10 +91,8 @@
 
 // ********** public function prototypes **********
 
-#ifndef ACK_NOT_IMPLEMENTED
 // ACK MSG
 BOOL sendACKMsg( MESSAGE_T *message );
-#endif
 
 // MSG_ID_DG_CHECK_IN
 void handleDGCheckIn( MESSAGE_T *message );